Heretofore, a semi-rigid polyurethane foam has been widely used as an interior member such as a crash pad for an instrument panel for automobiles and the like, because of its extremely superior properties for use as an impact absorption body. Most of pad materials for instrument panels are generally produced by a method in which a skin made from urethane or polyvinyl chloride and a base made from polypropylene are set in a mold and then a semi-rigid polyurethane foam raw solution is injected into the mold, followed by curing. As a method for producing a crash pad made from a semi-rigid polyurethane foam, the production method as disclosed in Patent Document 1 has been known.
However, the above-described production method has the problem that a curing time is long and moldability is insufficient. On the other hand, in the production method as disclosed in Patent Document 2, for example, curability and moldability can be improved to enhance productivity by using a polyol component comprising a polyol having a specific structure, a specific isocyanate component and a specific catalyst in combination.
In recent years, the improvement toward lightweights has been strongly demanded in order to enhance fuel economy, and a reduction in thickness in interior materials such as a crash pad has also been demanded. However, the above-described production method also has the problem that moldability is deteriorated when the thicknesses of such interior materials are reduced, in addition to the above-described problem.
In addition, in recent years, almost popular-priced automobiles are demanded to have high added values like luxury automobiles. For example, interior materials made from synthetic resins have been demanded to have a soft and resilient touch feel like a leather. In the above-described production methods, when the hardness of a semi-rigid polyurethane foam is reduced to improve the modulus of repulsion elasticity of the semi-rigid polyurethane foam, it is necessary to increase the molecular weight of a polyol component. As a result, the problem that the viscosity of a foam raw solution is increased and moldability becomes poor may occur.